Of all the genes in the human genome, the most common is the Alu sequence. These sequences insert into different places in the genome causing diseases. The diseases caused by such insertions are insertions into factor VIII and factor IX genes. Insertions into such important genes cause diseases like hemophilia.
A colleague hypothesizes that the Alu element prefers to insert into such sequences. I would not agree with his hypothesis. A transposable element inserts randomly into the genome. Most of the time the Alu sequences insert into non-coding regions or the introns. Such insertions do not harm or benefit the organism in any way. However, some insertions are in coding sequences. Hence, we cannot predict the location of insertion of the sequence.
A reason which might explain this data would be that there are about one million Alu sequences in the human genome. Some of them are inactive; some are regulated while some jump from place to place in the genome. Since, there are many such sequences it would be the reason for insertion into some coding regions in the genome.